Method for operating a brake system of a vehicle, and brake system

Abstract

A brake system, and a method for operating a brake system of a vehicle. To reduce a braking force, brake fluid is able to be discharged from the braking device via a cross-section adjusting member which connects a delivery device to the braking device, in a controlled and/or regulated manner, into an intermediate reservoir and is delivered to the main brake cylinder using the delivery device. The discharge of the brake fluid from the braking device of the brake system takes place, at least at times, at a discharge volume flow that is greater than the maximum delivery volume flow of the delivery device, and when a certain operating state of the braking system occurs, the discharge volume flow is reduced.

What is claimed is: 
     
       1. A method for operating a brake system of a vehicle, the brake system having at least one braking device assigned to a wheel of the vehicle, which is provided for applying a braking force to the wheel and to which brake fluid from a main brake cylinder is able to be supplied, and having a delivery device connected to the braking device via a cross-section adjusting member and an intermediate reservoir, the method comprising:
 discharging brake fluid from the braking device via the cross-section adjusting member, in at least one of a controlled and regulated manner, into the intermediate reservoir and delivering the brake fluid to the main brake cylinder using the delivery device, the discharging of the brake fluid from the braking device of the brake system taking place, at least at times, at a discharge volume flow that is greater than a maximum delivery volume flow of the delivery device; and 
 reducing the discharge volume flow when a certain operating state of the brake system occurs, 
 wherein the cross-section adjusting member equalizes the pressure discharged from the at least one braking device using at least one valve. 
 
     
     
       2. The method as recited in  claim 1 , wherein the certain operating state is at least one of a malfunction of the delivery device, and an exceeding of a certain fluid level of the intermediate reservoir. 
     
     
       3. The method as recited in  claim 2 , wherein the discharge volume flow at the malfunction is selected to be equal to or less than the maximum delivery volume flow. 
     
     
       4. The method as recited in  claim 2 , further comprising:
 monitoring an operating voltage of the delivery device, the malfunction being indicated in response to an undershooting of a certain minimum voltage. 
 
     
     
       5. The method as recited in  claim 2 , wherein the fluid level of the intermediate reservoir is determined with the aid of a fluid level model. 
     
     
       6. The method as recited in  claim 5 , wherein the fluid level model has as input variables the discharge volume flow and at least one operating variable of the delivery device. 
     
     
       7. The method as recited in  claim 6 , wherein the at least one operating variable is an operating voltage of the delivery device. 
     
     
       8. The method as recited in  claim 5 , wherein the discharge volume flow is reduced if the determined fluid level exceeds a threshold fluid level. 
     
     
       9. The method as recited in  claim 5 , wherein the fluid level of the intermediate reservoir is further determined with the aid of at least one sensor. 
     
     
       10. The method as recited in  claim 1 , wherein a plurality of braking devices is connected to the intermediate reservoir. 
     
     
       11. The method as recited in  claim 1 , wherein, to reduce the discharge volume flow, discharging the brake fluid less often and in lesser quantities from the braking device by performing at least one of: i) supplying a lower volume flow of the brake fluid from the main brake cylinder, ii) selecting a greater waiting time between attaining a specified pressure in the braking device and the discharging of the brake fluid, and iii) reducing a specified pressure to be attained during the supplying of the brake fluid. 
     
     
       12. The method as recited in  claim 1 , wherein for reducing the discharge volume flow in the case of a plurality of braking devices, a wheel having a greatest blocking inclination is not taken into account for the at least one of the control and the regulation of the discharging of the brake fluid. 
     
     
       13. The method as recited in  claim 12 , wherein in the case of the plurality of braking devices, each device is assigned to one of the wheels of the vehicle. 
     
     
       14. The method as recited in  claim 1 , wherein the delivery device is connected to at least four braking devices via the cross-section adjusting member and an intermediate reservoir, wherein to reduce the braking force, brake fluid is discharged from the at least four braking devices via the cross-section adjusting member, in at least one of a controlled and regulated manner, into the intermediate reservoir and is delivered to the main brake cylinder using the delivery device. 
     
     
       15. A brake system of a vehicle, comprising:
 at least one braking device assigned to a wheel of the vehicle, which is provided for applying a braking force to the wheel and to which brake fluid from a main brake cylinder is able to be supplied; and 
 a delivery device connected to the braking device via a cross-section adjusting member and an intermediate reservoir, wherein to reduce the braking force, brake fluid is discharged from the braking device via the cross-section adjusting member, in at least one of a controlled and regulated manner, into the intermediate reservoir and is delivered to the main brake cylinder using the delivery device; 
 wherein the brake system is configured so that the discharge of the brake fluid from the braking device of the brake system takes place, at least at times, at a discharge volume flow that is greater than a maximum delivery volume flow of the delivery device, and when a certain operating state of the braking system occurs, the discharge volume flow is reduced, and wherein the cross-section adjusting member equalizes the pressure discharged from the at least one braking device using at least one valve. 
 
     
     
       16. The brake system as recited in  claim 15 , wherein the delivery device is connected to at least four braking devices via the cross-section adjusting member and an intermediate reservoir, wherein to reduce the braking force, brake fluid is discharged from the at least four braking devices via the cross-section adjusting member, in at least one of a controlled and regulated manner, into the intermediate reservoir and is delivered to the main brake cylinder using the delivery device.